Marin air good, could be better, American Lung Association says

That is the word from the American Lung Association, which issued its annual "State of the Air" report card on Wednesday.

Marin received an "A" for its ozone air quality, joining Bay Area counties Sonoma and San Francisco. But when it comes to soot, or particulate matter Marin received a "C" grade.

"That is from the wintertime when people are burning in their fireplaces," said Jenny Bard, regional director of the American Lung Association. "Marin's air quality is good, but it can do better. But it does a great job overall of promoting biking, walking and transit over cars."

Bad air can have an impact on the county's most vulnerable residents, officials said. In Marin, 18,330 adults have asthma as do 4,611 children, according to the lung association report. Another 10,979 people in the county have chronic obstructive pulmonary disease.

The 15th annual report measured how many days each county exceeded federal health standards for ground-level ozone, commonly called smog, and fine particle pollution during 2010, 2011 and 2012.

The lung association tallied the total number of days in which smog and soot exceeded air quality standards and then assigned grades. For ozone, counties could not exceed the federal standard of an average of 3.3 days during each of the three years to earn an "A." If they had more than three days a year, they were given an "F." Marin averaged 1.3 such days for each of the three years tallied.

The particulate matter data for the report was drawn from an air monitor in San Rafael. Susan Goldsborough, executive director of the Mill Valley-based Families for Clean Air, said samples should be drawn from other areas, such as one of Marin's valleys, where smoke can gather and linger, for a more accurate assessment of air quality.

"If we really knew the true neighborhood conditions during the winter as far as levels of wood smoke goes our grade would be much lower," she said.

Only Sonoma County received an "A" for particulate matter, according to the report.

Overall, the Bay Area shows success in reducing ozone and particulate pollution over the years of the reports. Unhealthy ozone days have fallen by 77 percent since the 2000 report, and spikes in particulate pollution days have dropped by 86 percent since 2004. This year's report shows all counties in the region earned passing grades for year-round particulate pollution, according to the lung association.

California experienced small increases in the number of ozone polluted days compared to last year's report, but had more consistent reductions in short-term particle days and lower year-round particle levels, according to the report.

As of 2013, San Joaquin County was included in the Bay Area metropolitan area by the federal government, resulting in a significant increase in the number of unhealthy days for ozone and particle pollution reported for the region. With the addition, the Bay Area region now ranks among the top 10 areas most polluted by particulates in the nation.